WASHINGTON -- Childhood epilepsy surgery isn't associated with
a long-term improvement in cognitive functioning, Janet Olds, Ph.D., and
her colleagues reported in a poster at the joint annual meeting of the
American Epilepsy Society and the American Clinical Neurophysiology
Society.

While findings from previous studies have shown that the surgery
has no short-term effect on childhood cognition, little was known until
now about its long-term effect on adult cognition, noted Dr. Olds, a
psychologist at the Children's Hospital of Eastern Ontario.

She assessed cognitive function in 50 adults (mean age 22 years)
with a history of childhood epilepsy; 34 had undergone epilepsy surgery
at least 2 years prior to assessment.

Of these, 21 were seizure-free and 13 continued to have seizures.
The other 16 subjects, who served as controls, had never had surgery for
their epilepsy as children and continued to have seizures as adults.

Seizure-free surgical subjects were taking a mean of one
antiepileptic drug. Both the surgical group with continued seizures and
the nonsurgical group were taking a mean of two antiepileptic drugs.

All of the subjects completed a neuropsychological assessment
consisting of measures of intelligence, memory, and executive
functioning (Wechsler Adult Intelligence Scale, vocabulary and block
design; Wechsler Memory Scale, logical memory and memory for faces;
Wisconsin Card Sort Test). Scores were compared with the subjects'
pre- and postsurgical scores on the same tests.

There were no group differences in problem solving as reflected in
the Wisconsin Card Sort Test. Surgery subjects who continued to have
seizures scored lower on vocabulary and verbal memory tests, compared
with both the seizure-free surgery group and the no-surgery group.

When the scores in two surgical groups were compared, the
seizure-free group did better on vocabulary and block design, compared
with the group still having seizures. However, there were no differences
in scores across the three test periods, indicating no significant
change in functioning over time.

It's important to include a discussion of cognitive function
when counseling parents about the potential impact of epilepsy surgery,
said Mary Lou Smith, Ph.D., the study's principal investigator. The
majority of research suggests that cognitive skills won't change--a
fact that can be construed in a positive, as well as potentially
negative, light.

"In essence, this is good news, although not necessarily the
good news those parents would like to hear," Dr. Smith, of the
University of Toronto, said in an interview. "[Parents] may wish,
and often do, that their child will show improved cognitive function
after surgery."

She added that it is important to remember that the study's
conclusions are based on group numbers and that within each group, some
children do better or worse than the study's findings indicate.

Unfortunately, Dr. Smith said, there's no consensus on what
factors predict who will improve and who will deteriorate.

"The few studies that have included a comparison group of
children with intractable epilepsy who don't have surgery show that
the proportion who shows increases or decreases is the same in both
surgical and nonsurgical groups," she commented.

The general conclusion is that as long as the eloquent cortex
remains intact, there is no particular cognitive risk or benefit
associated with the surgery, said Dr. Smith.

BY MICHELE G. SULLIVAN

Mid-Atlantic Bureau

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